python连接MySQL、MongoDB、Redis、memcache等数据库的方法


            用Python写脚本也有一段时间了，经常操作数据库（MySQL），现在就整理下对各类数据库的操作，如后面有新的参数会补进来，慢慢完善。

一，python 操作 MySQL:详情见：【apt-get install python-mysqldb】

复制代码 代码如下:#!/bin/env python# -*- encoding: utf-8 -*-#-------------------------------------------------------------------------------# Purpose:     example for python_to_mysql# Author:      zhoujy# Created:     2013-06-14# update:      2013-06-14#-------------------------------------------------------------------------------import MySQLdbimport os

#建立和数据库系统的连接，格式#conn   = MySQLdb.connect(host='localhost',user='root',passwd='123456',db='test',port=3306,charset='utf8')

#指定配置文件，确定目录,或则写绝对路径cwd = os.path.realpath(os.path.dirname(__file__))db_conf = os.path.join(cwd, 'db.conf')conn   = MySQLdb.connect(read_default_file=db_conf,host='localhost',db='test',port=3306,charset='utf8')

#要执行的sql语句query  = 'select id  from t1'

#获取操作游标cursor = conn.cursor()

#执行SQLcursor.execute(query)

#获取一条记录,每条记录做为一个元组返回,返回3，游标指到第2条记录。result1 = cursor.fetchone()for i in result1:    print i#返回影响的行数    print cursor.rowcount

#获取指定数量记录,每条记录做为一个元组返回,返回1，2，游标从第2条记录开始，游标指到第4条记录。result2 = cursor.fetchmany(2)for i in result2:    for ii in i:        print ii

#获取所有记录,每条记录做为一个元组返回,返回3，4，7，6,游标从第4条记录开始到最后。result3 = cursor.fetchall()for i in result3:    for ii in i:        print ii

#获取所有记录,每条记录做为一个元组返回,返回3，4，7，6,游标从第1条记录开始#重置游标位置，0为偏移量，mode＝absolute | relative,默认为relativecursor.scroll(0,mode='absolute')result3 = cursor.fetchall()for i in result3:    for ii in i:        print ii

#以下2种方法都可以把数据插入数据库：#(one)for i in range (10,20):    query2 = 'insert into t1 values("%d",now())' %i    cursor.execute(query2)    #提交    conn.rollback()#(two)rows = []for i in range (10,20):    rows.append(i)query2 = 'insert into t1 values("%s",now())'#executemany 2个参数,第2个参数是变量。cursor.executemany(query2,rows)#提交conn.commit()

#选择数据库query3 = 'select id from dba_hospital'#重新选择数据库conn.select_db('chushihua')

cursor.execute(query3)

result4 = cursor.fetchall()for i in result4:    for ii in i:        print ii#不定义query，直接执行：cursor.execute("set session binlog_format='mixed'")

#关闭游标，释放资源cursor.close()

'''+------+---------------------+| id   | modifyT             |+------+---------------------+|    3 | 2010-01-01 00:00:00 ||    1 | 2010-01-01 00:00:00 ||    2 | 2010-01-01 00:00:00 ||    3 | 2010-01-01 00:00:00 ||    4 | 2013-06-04 17:04:54 ||    7 | 2013-06-04 17:05:36 ||    6 | 2013-06-04 17:05:17 |+------+---------------------+

'''

注意：在脚本中，密码写在脚本里面很容易暴露，这样可以用一个配置文件的方式来存密码，如db.conf：

复制代码 代码如下:[client]user=rootpassword=123456

二，python 操作 MongoDB:

复制代码 代码如下:#!/bin/env python# -*- encoding: utf-8 -*-#-------------------------------------------------------------------------------# Purpose:     example for python_to_mongodb# Author:      zhoujy# Created:     2013-06-14# update:      2013-06-14#-------------------------------------------------------------------------------import pymongoimport os

#建立和数据库系统的连接,创建Connection时，指定host及port参数conn   = pymongo.Connection(host='127.0.0.1',port=27017)

#admin 数据库有帐号，连接-认证-切换库db_auth = conn.admindb_auth.authenticate('sa','sa')#连接数据库db = conn.abc

#连接表collection = db.stu

#查看全部表名称db.collection_names()#print db.collection_names()

#访问表的数据，指定列item = collection.find({},{"sname":1,"course":1,"_id":0})for rows in item:    print rows.values()

#访问表的一行数据print collection.find_one()

#得到所有的列for rows in collection.find_one():    print rows

#插入collection.insert({"sno":100,"sname":"jl","course":{"D":80,"S":85}})#或u = dict(sno=102,sname='zjjj',course={"D":80,"S":85})collection.insert(u)

#得到行数print collection.find().count()print collection.find({"sno":100})

#排序，按照某一列的值。pymongo.DESCENDING:倒序；pymongo.ASCENDING:升序。按照sno倒序item = collection.find().sort('sno',pymongo.DESCENDING) for rows in item:    print rows.values()

#多列排序item = collection.find().sort([('sno',pymongo.DESCENDING),('A',pymongo.ASCENDING)])

#更新，第一个参数是条件，第二个参数是更新操作，$set,%inc,$push,$ne,$addToSet,$rename 等collection.update({"sno":100},{"$set":{"sno":101}})#更新多行和多列collection.update({"sno":102},{"$set":{"sno":105,"sname":"SSSS"}},multi=True)

#删除，第一个参数是条件，第二个参数是删除操作。collection.remove({"sno":101})

'''sno:学号；sname：姓名；course：科目

db.stu.insert({"sno":1,"sname":"张三","course":{"A":95,"B":90,"C":65,"D":74,"E":100}})db.stu.insert({"sno":2,"sname":"李四","course":{"A":90,"B":85,"X":75,"Y":64,"Z":95}})db.stu.insert({"sno":3,"sname":"赵五","course":{"A":70,"B":56,"F":85,"G":84,"H":80}})db.stu.insert({"sno":4,"sname":"zhoujy","course":{"A":64,"B":60,"C":95,"T":94,"Y":85}})db.stu.insert({"sno":5,"sname":"abc","course":{"A":87,"B":70,"Z":56,"G":54,"H":75}})db.stu.insert({"sno":6,"sname":"杨六","course":{"A":65,"U":80,"C":78,"R":75,"N":90}})db.stu.insert({"sno":7,"sname":"陈二","course":{"A":95,"M":68,"N":84,"S":79,"K":89}})db.stu.insert({"sno":8,"sname":"zhoujj","course":{"P":90,"B":77,"J":85,"K":68,"L":80}})db.stu.insert({"sno":9,"sname":"ccc","course":{"Q":85,"B":86,"C":90,"V":87,"U":85}})

'''

计算Mongodb文档中各集合的数目：

复制代码 代码如下:import pymongo

conn   = pymongo.Connection(host='127.0.0.1',port=27017)db = conn.abc    #abc文档for tb_name in db.collection_names():     #循环出各集合名    Count = db[tb_name].count()            #计算各集合的数量    if Count > 2:                                 #过滤条件        print tb_name + ':' + str(Count) 

'''conn   = pymongo.Connection(host='127.0.0.1',port=27017)db = conn.abcfor tb_name in db.collection_names():    print tb_name + ':'     exec('print ' + 'db.'+tb_name+'.count()')      #变量当集合的处理方式

OR

conn   = pymongo.Connection(host='127.0.0.1',port=27017)db = conn.abcfor tb_name in db.collection_names():    mon_dic=db.command("collStats", tb_name)      #以字典形式返回    print mon_dic.get('ns'),mon_dic.get('count')

'''

三，python 操作 Redis:

复制代码 代码如下:#!/bin/env python# -*- encoding: utf-8 -*-#-------------------------------------------------------------------------------# Purpose:     example for python_to_mongodb# Author:      zhoujy# Created:     2013-06-14# update:      2013-06-14#-------------------------------------------------------------------------------

import redis

f = open('aa.txt')while True:    line = f.readline().strip().split(' # ')    if line == ['']:        break    UserName,Pwd,Email = line#    print name.strip(),pwd.strip(),email.strip()    rc = redis.StrictRedis(host='127.0.0.1',port=6379,db=15)    rc.hset('Name:' + UserName,'Email',Email)    rc.hset('Name:' + UserName,'Password',Pwd)f.close()

alluser = rc.keys('*')#print alluserprint "===================================读出存进去的数据==================================="for user in alluser:    print ' # '.join((user.split(':')[1],rc.hget(user,'Password'),rc.hget(user,'Email')))

四，python 操作 memcache:

复制代码 代码如下:import memcachemc = memcache.Client(['127.0.0.1:11211'],debug=1)

复制代码 代码如下:#!/usr/bin/env python#coding=utf-8import MySQLdbimport memcacheimport sysimport time

def get_data(mysql_conn):#    nn = raw_input("press string name:")    mc = memcache.Client(['127.0.0.1:11211'],debug=1)    t1 =time.time()    value = mc.get('zhoujinyia')     if value == None:        t1 = time.time()        print t1        query = "select company,email,sex,address from uc_user_offline where realName = 'zhoujinyia'"        cursor= mysql_conn.cursor()        cursor.execute(query)        item = cursor.fetchone()        t2 = time.time()        print t2        t = round(t2-t1)        print "from mysql cost %s sec" %t         print item        mc.set('zhoujinyia',item,60)    else :        t2 = time.time()        t=round(t2-t1)        print "from memcache cost %s sec" %t        print valueif __name__ =='__main__':    mysql_conn = MySQLdb.connect(host='127.0.0.1',user='root',passwd='123456',db='member',port=3306,charset='utf8')    get_data(mysql_conn)